The invention relates generally to guide catheters, and more particularly to guide catheters utilizing a balloon actuated, selectively shapeable distal tip.
Guiding catheters are instruments that allow a physician to locate and cannulate vessels in a patient""s heart for performing various medical procedures, including venography and implanting of cardiac pacing devices. Cannulating heart vessels requires navigating a small diameter, flexible guide through the convoluted vasculature into a heart chamber, and then into a destination heart vessel. Once the destination heart vessel is reached, the catheter acts as a conduit for insertion of payloads into the vessel.
A commonly accessed destination vessel for cardiac pacing lead insertion is the coronary sinus. A pre-shaped guiding catheter is typically used to blindly locate the coronary sinus ostium. This endeavor, however, is complicated by the fact that the location of the coronary sinus ostium may vary appreciably from one patient to another, especially among patients with diseased hearts. Oftentimes, the clinician is entirely unable to locate the coronary sinus ostium using the guiding catheter, and must resort to finding the ostium by xe2x80x9cmappingxe2x80x9d (interpreting localized bipolar waveforms) using an electrophysiological (EP) catheter and an ECG monitor. After the ostium is located, the guiding catheter is typically used to inject radiographic contrast media into the coronary sinus to highlight the associated venous system, and then a pacing lead is installed within one of the coronary branches.
Complicating this scenario is the dynamic structural deformation of the heart chambers that occurs from normal cardiac activity during the procedure. This further increases the difficulty of guiding a catheter to its destination. Presently, a considerable amount of time is often spent by the physician when manipulating such catheters within cardiac structures, such as the right atrium, simply trying to locate an anatomical feature of interest, such as the coronary sinus ostium.
Guiding catheter systems are typically configured with a profile that is optimized for the intended method of access. In the case of accessing the coronary sinus via the right atrium, a catheter with a distal contour including a relatively sharp bend will point the catheter towards the likely location of the coronary sinus once the right atrium is reached. The contours of pre-shaped guiding catheters are generally fixed, and this is typically achieved in production by constraining the distal end within a shaping fixture while warming them until they assume the intended shape (i.e., by xe2x80x9cheat settingxe2x80x9d their polymer shaft).
A fixed shape catheter is adequate in many cases where the pathway is not significantly convoluted and the pathway does not deviate significantly between patients. In situations where structural anomalies or significant variations exist, use of a fixed shape catheter may require that the clinician stock multiple size and shapes of catheters to account for potential variations. Fixed shape catheters may require a time consuming trial and error process of inserting and removing different shapes until the destination vessel is successfully accessed.
Steerable catheters are also used for various guiding applications. Steerable catheters typically rely on an integral steering mechanism which includes a mechanical linkage to a deflection point at the catheter""s distal end. These devices can be effective in allowing dynamic reshaping of the catheter""s distal end, however they are not ideal for all situations. The linkage usually has some clearance within the lumen to allow for easier longitudinal movement of the linkage. The clearance can result in backlash when the steering mechanism is operated. Depending on the length and deployed shape of the catheter, backlash of a steered catheter may render it difficult to operate.
There is a need for an improved guide catheter for accessing heart vessels that can dynamically account for anatomical variations and defects associated with the destination structures. The present invention fulfills these and other needs, and addresses other deficiencies of prior art implementations and techniques.
To overcome the limitations in the prior art described above, and to overcome other limitations that will become apparent upon reading and understanding the present specification, the present invention discloses a steerable guide catheter that can provide access to venous structures for medical procedures.
According to one embodiment of the invention, a guide catheter includes a flexible shaft having a pre-shaped distal bend and an inflation lumen. An inflatable member is disposed on an external surface of the flexible shaft in fluid connection with the inflation lumen. The inflatable member encompasses at least part of the pre-shaped distal bend of the flexible shaft. Inflation and deflation of the inflatable member changes a shape of the pre-shaped distal bend. The guide catheter includes an inflation mechanism in fluid connection with a proximal end of the inflation lumen. The inflation mechanism selectably pressurizes and depressurizes the fluid within the inflation lumen to respectively inflate and deflate the inflatable member.
According to another embodiment of the present invention, the guide catheter includes a flexible shaft having a pre-shaped distal bend, an inflation lumen, and an inflatable section disposed along at least part of the pre-shaped distal bend. The inflatable section is in fluid connection with the inflation lumen. The inflatable section changes a shape of the pre-shaped distal bend upon inflation and deflation of the inflatable section. An inflation mechanism is in fluid connection with a proximal end of the inflation lumen. The inflation mechanism selectably pressurizes and depressurizes the fluid within the inflation lumen to respectively inflate and deflate the inflatable section.
In one configuration, the flexible shaft may further include an open lumen. The open lumen can be adapted to receive a payload. The open lumen can also be adapted to receive an injection of a contrast media for mapping blood vessels.
In one arrangement, the inflation lumen is disposed along an external surface of the flexible shaft. In an alternate arrangement, the inflation lumen is disposed within the flexible shaft. In a configuration of a guide catheter according to the present invention, the inflatable member comprises an occlusion balloon.
The inflatable member can be arranged to encompass a partial circumferential angle of a cross section of the flexible shaft. The partial circumferential angle in this arrangement can range from about 90 degrees to about 180 degrees.
In one configuration of a catheter according to the present invention, a distal end of the flexible shaft is steerable by rotation of a proximal end of the flexible shaft. The guide catheter may further include at least one electrode disposed on a distal end of the flexible shaft and at least one electrical conductor disposed along the flexible shaft and coupled to the at least one electrode.
In an embodiment of the present invention, a method of inserting a guide catheter into a patient""s blood vessel includes providing a guide catheter. The guide catheter includes a flexible shaft having a pre-shaped distal bend, an inflation lumen, and an inflatable section disposed along at least part of the pre-shaped distal bend. The inflatable section is in fluid connection with the inflation lumen. The inflatable section changes a shape of the pre-shaped distal bend upon inflation and deflation of the inflatable section. An inflation mechanism is in fluid connection with a proximal end of the inflation lumen. The inflation mechanism selectably pressurizes and depressurizes the fluid within the inflation lumen to respectively inflate and deflate the inflatable section.
The method further involves inserting a distal end of the flexible shaft through the patient""s venous system via an access vessel. The inflation mechanism is actuated to selectably inflate and deflate the inflatable section. Inflating and deflating the inflation mechanism changes the shape of the pre-shaped distal bend for finding and cannulating the blood vessel.
The method can further involve, after finding and cannulating the blood vessel, distally advancing the flexible shaft to seat the distal end of the flexible shaft in the blood vessel. A payload is then inserted through a proximal end of the flexible shaft for implanting the payload into the blood vessel. The payload may include a pacing lead. In another aspect, the payload may include an occlusion device.
The method can also involve injecting a contrast media into the flexible shaft for mapping of blood vessels after finding and cannulating the blood vessel. In one aspect of the method, the blood vessel is the coronary sinus of the patient""s heart and the access vessel is the right atrium accessed via the superior vena cava.
The above summary of the present invention is not intended to describe each embodiment or every implementation of the present invention. Advantages and attainments, together with a more complete understanding of the invention, will become apparent and appreciated by referring to the following detailed description and claims taken in conjunction with the accompanying drawings.